Doctor Internet Will Misdiagnose You Now

Technology has insidiously infiltrated all manner of industry.  Many tasks, originally accomplished by humans, have been replaced by computers and robots.  All manner of industrialization is now automated, Deep Blue wins at chess, and Watson wins at Jeopardy!

But, don’t rely on Internet symptom checkers to replace your regular physician.

These authors evaluated 23 different online symptom checkers, ranging from the British National Health Service Symptom Checker to privately owned reference sites such as WebMD, with a variety of underlying methodologies.  The authors fed each symptom checker 45 different standardized patient vignettes, ranging in illness severity from pulmonary embolism to otitis media.  The study evaluated twin goals: are the diagnoses generated accurate?  And, do the tools triage patients to the correct venue for medical care?


For symptom checkers providing a diagnosis, the correct diagnosis was provided 34% of the time.  This seems pretty decent – until you go further into the data and note these tools left the correct diagnosis completely off the list another 42% of the time.  Most tools providing triage information performed well at referring emergent cases to high levels of care, with 80% sensitivity.  However, this performance was earned by simply referring the bulk of all cases for emergency evaluation, with 45% of non-emergent and 67% of self-care cases being referred to inappropriate levels of medical care.

Of course, this does not evaluate the performance of these online checkers versus telephone advice lines, or even against primary care physicians given the same limited information.  Before being too quick to tout these results as particularly damning, they should be evaluated in the context of their intended purpose.  Unfortunately, due to their general accessibility and typical over-triage, they are likely driving patients to seek higher levels of care than necessary.

“Evaluation of symptom checkers for self diagnosis and triage: audit study”